Apparatus for use in processing curd in the manufacture of cheese

ABSTRACT

A cheese curd processing machine in which curd is fed over a screen to a first conveyor on which it forms a layer, the conveyor being operated in use at a speed so as to form a layer of curd of convenient depth for whey drainage purposes, and the layer being stirred by means of a series of rakes which are moved in succession along its length from the infeed to the outfeed end thereof at a speed greater than the speed of the conveyor. Curd from the layer may then be transferred to a second conveyor, the effective speed of which is less than the speed of the first conveyor so that the depth of curd on the second conveyor is greater to facilitate consolidation during the second conveying stage.

United States Patent [19] Leonard Nov. 20, 1973 APPARATUS FOR USE INPROCESSING CURD IN THE MANUFACTURE or CHEESE [73] Assignee: Bell BryantPty. Ltd.,Kensington,

. Victoria, Australia [22] Filed: July 23, 1971 [21] Appl. No.: 165,687

[30] Foreign Application Priority Data Pontecorvo Hensgen et al.

8/1970 Czulak 31/89 2/1971 Nikolic 31/46 Primary Examiner-Aldrich F.Medbery Attorney--Cushman, Darby & Cushman [57] ABSTRACT A cheese curdprocessing machine in which curd is fed over a screen to a firstconveyor on which it forms a layer, the conveyor being operated in useat a speed so as to form a layer of curd of convenient depth for wheydrainage purposes, and the layer being stirred by means of a series ofrakes which are moved in succession along its length from the infeed tothe outfeed end thereof at a speed greater than the speed of theconveyor. Curd from the layer may then be transferred to a secondconveyor, the effective speed of which is less than the speed of thefirst conveyor so that the depth of curd on the second conveyor isgreater to facilitate consolidation during the second conveying stage.

5 Claims, 3 Drawing Figures PAIENTEDnnvzo I975 v 7 37720786 SHEET 2 or 3PAIENTEDHHV 20 I975 SHEET 3 BF 3 ummmm The present invention relates toa method and apparatus for use in processing of curd in the productionof 5 cheese. It is intended particularly but not exclusively for use inthe manufacture of cheddar and like cheeses, in the production of whichthe curd is intended to consolidate.

In Australian Patent Application No. 26955/67 there is described amethod and apparatus for draining whey from curd. Briefly the methoddisclosed therein comprised the steps of passing a mixture of curd andwhey over a screen to effect an initial separation of the whey from thecurd, passing the curd and remaining whey to a conveyor belt formed tocause or allow the whey to drain from the curd which forms a layer onthe belt, and applying lifting forces to the curd on the conveyor beltto facilitate drainage of whey therefrom. The reader is referred to theappropriate specification for full details of the method.

The invention disclosed in Australian Application No. 26955/67 wasintended particularly for use in production of Colby cheese, stirredcurd cheese, and hard grating cheese of the Romano type. In suchproduction, the layer of curd formed on the conveyor would be stirredalong the full length of the conveyor and would not be permitted toconsolidate thereon. However, the method and apparatus could also beused for production of Cheddar or like cheese by terminating theapplication of lifting forces at a comparatively early stage, andthereafter permitting the layer of curd to consolidate on the belt.Australian Patent Application No.

50076/69 describes a method and apparatus for producing cheese of theCheddar type in which apparatus generally in accordance with Application26955/67 is used to drain the curd, preparatory to separation ofindividual blocks from the consolidated layer of curd, and transfer ofthe blocks to a compression conveyor on which the curd in the blocks iscaused to flow to produce fibre developement.

The drainage system described in Application No. 26955/67 has been foundto give good results in production of Colby or Romano cheeses. It hasalso been found satisfactory in the production of Cheddar or likecheeses provided the layer of curd on the drainage conveyor is not toodeep. In the production of Cheddar cheese, however, it is desired tomake the layer of curd on the drainage conveyor of considerable depth sothat consolidation of the lower part of the layer is obtained throughgravity. When the layer of curd is made deep it has been found that thestirrers which apply the lifting forces to the curd constitute aconsiderable impedance to movement of curd with the conveyor, and causebanking of the layer of curd behind them. This can cause prematurecheddaring of the curd while it still contains a considerable quantityof whey, and the whey may be trapped in the cheddared mass.

According to a first aspect of the present invention therefore there isprovided apparatus for use in processing curd in the manufacture ofcheese comprising first and second conveyor means arranged such thatcurd from a layer of curd formed on the first conveyor means can betransferred to the second conveyor means so as to form a body of curdthereon, the first and second conveyor means being operable at differenteffective speeds so that the depth of the layer on the first conveyormeans can be made less than the depth of the body on the second conveyormeans.

The arrangement may be such that the layer of curd formed on the firstconveyor means is continuous with a layer formed on the second conveyormeans. The first conveyor means is preferably operable at a speed suchthat the depth of the layer formed thereon permits a desired degree ofdrainage of liquid prior to transfer of the curd to the second conveyormeans. Curd stirring means may be associated with the first conveyormeans so as to facilitate drainage of liquid from a layer of curd formedon that conveyor means.

The depth of the body on the second conveyor means and the time forwhich it remains on this conveyor means may be made such as to obtain adesired degree of consolidation of the curd, for instance to permitfurther processing by a method as disclosed in Application No. 50076/69.

This aspect of the invention includes provision of a method for use inprocessing curd in the manufacture of cheese comprising the steps offorming a layer of curd on a first conveyor means, while operating saidconveyor means at an effective speed such as to produce a desired depthof layer thereon, and transferring curd from said layer to a secondconveyor means so as to form a body of curd thereon, while operating thesecond conveyor means at an effective speed such as to produce a depthof curd which is greater than the first mentioned depth.

Preferably the layer of curd on the first conveyor means is continuouswith a layer formed on the second conveyor means. The depth of the layeron the first conveyor means is preferably such as to permit a desireddegree of drainage of liquid prior to transfer of the curd to the secondconveyor means. Preferably, the method includes the step of stirring thelayer of curd on the first conveyor means to facilitate drainage of wheytherefrom.

According to a second aspect of the invention there is providedapparatus for use in processing curd in manufacture of cheese comprisinga conveyor arranged to convey a body of curd and a plurality of curdstirring devices movable in succession along an elongated path whichextends along the conveyor in the direction of movement of the body ofcurd while extending into the body of curd to stir it. This aspect ofthe invention includes a corresponding method comprising the steps offorming a body of curd on a conveyor and stirring said body of curd bymeans of said devices.

Preferably the path extends forwardly of the conveyor from the infeedend thereof, and the path may be arranged to extend over substantiallythe full length of the conveyor. Preferably, too the speed of movementof the stirring devices along the path is greater than the speed of thecurd in the same direction. Each stirring device may comprise aplurality of fingers spaced transversely of the path while being movedalong it.

According to a feature of this second aspect of the invention, theconveyor for conveying the body of curd may be the first conveyor meansreferred to in the first aspect of the invention described above.

By way of example, one embodiment of an apparatus in accordance with theinvention will now be described with reference to the accompanyingdrawings, in which:

FIG. 1 is a diagrammatic perspective view of the infeed end of a curddrainage and consolidation system,

FIG. 2 is a diagrammatic side elevation of the apparatus shown in FIG.1, and

FIG. 3 is a perspective view of part of an arrangement of stirringblades alternative to the tine arrangement shown in FIGS. 1 and 2 Theapparatus shown in the Figures is intended especially for production ofCheddar type cheese. In use of the illustrated apparatus, a curd/wheymixture is fed by a pipe, the end of which is indicated at in theFigures, on to an inclined screen 12. The pipe is swivel mounted foroscillatory movement across the width of the screen so that thecurd/whey mixture is spread evenly across it. Most of the whey passesthrough the screen into whey tanks disposed beneath the illustratedapparatus, while the curd forms a layer on the screen.

The lower end of screen 12 is curved to lead on to a first conveyor belt14. The belt is similar to that disclosed in Application No. 26955/67,being constituted by a continuous band of polyethylene mounted on endrollers 16 and intermediate guide rollers 18. Stainless steel guidewalls 17 are provided to maintain a curd layer of desired depth on thebelt. As best seen in FIG. 2, the upper run of the belt is inclinedupwardly at a small angle to the horizontal away from the end of screen12. An angle of 9 is suitable.

It will be noted however that conveyor belt 14 is short in comparisonwith the conveyor belt described in Application 26955/67 and at the endof belt 14 remote from the screen the layer of curd is transferred to afurther conveyor belt 20. This belt is also of similar construction tothe belt described in Application 2695 5/67, the upper run of conveyorbelt 20 is substantially horizontal in the longitudinal direction thoughcrowned to the longitudinal centre line.

In use, conveyor belt 14 is driven by a suitable drive system (notshown) so that curd received from screen 12 forms a layer on the upperrun of the belt and is conveyed thereby to belt 20. Belt 14 is driven ata speed such that for a given throughput of curd defined by the amountfed from pipe 10, a layer of curd of desired thickness is formed on thebelt. The thickness of the layer will be such as to permit adequatedrainage of whey while the curd is in a non-consolidated state. Conveyorbelt 20 will be driven at a different speed such that the layer of curdon that belt is substantially deeper than the layer on belt 14. This,together with suitable choice of the length of belt 20, will permitconsolidation of the layer on the conveyor belt by gravity, so that thecurd leaving this conveyor can be treated by the subsequent processingsteps described in Application No. 50076/69.

Disposed above belt 14 is a curd stirring apparatus comprising two pairsof sprockets 22 and 24 respectively. Sprockets 22 are mounted on and forrotation with a shaft 26 carried on the frame of the machine above thelower end of screen 12. Shaft 26 is in use driven by a motor and geararrangement diagrammatically indicated at 28. Sprockets 24 are mountedon and for rotation with a shaft 30 carried in the machine frame abovethe other end of belt 14; they are interconnected with sprockets 22 byrespective chains 32. In use, chains 32 are driven in the opposite senseto belt 14 so that the upper run of the belt and the lower run of thechains travel in the same direction.

Four crossbars 34 are mounted between chains 32 so as to be equallyspaced along the path of travel defined by the chains. Each crossbarcarries a plurality of tines 36 which project downwardly from their barwhen it is moving along the lower run of the chains so that the tinesthen extend into the layer of curd on belt 14. The speed of travel ofthe chains is made greater than the speed of travel of the belt, so thatthe tines move through the layer of curd and form channels in it. Thesuccessive sets of tines are staggered so that the channels formed byone set fall between the channels formed by the preceding set.

As can be seen in FIG. 2, as the tines rotate from the upper run to thelower run of the chains, they enter the curd falling from the screen 12on to the belt 14. They then progress through the layer of curd formedon the conveyor, and the channels opened up by this movement permitrun-off of whey from the layer back towards the screen; this isfacilitated by the inclination of belt 14. The speed of operation of thechains relative to belt 14 can be adjusted to give a very gentlestirring action which nevertheless permits the required run-off of whey.It will be noticed that since the stirring tines move in the samedirection as the curd along belt 14, there will be no tendency for curdto bank up behind the tines and therefore no tendency for prematurecheddaring to occur. Also, it will be noticed that at this stage belt 14is being operated at a speed such that the layer formed on it iscomparatively shallow, and therefore very effective drainage can beobtained.

In a machine designed to process 6,000 lbs of curd per hour, forproduction of Cheddar cheese, the width of belt 14 may be about 4 ft. 8inches, and equal to the width of belt 20. In this case, six to eightstirring fingers may be provided on each crossbar with approximatelyeven spacing between adjacent fingers. Belt 14 may have an upper runabout 10 feet long and may be run at a linear speed of 1 foot per minuteto produce a curd depth of about 6 inches. The chain speed may then beabout 30 feet per minute. Belt 20 may have an upper run such that thecurd travels about 18 feet, and may be run at a linear speed of about 6inches per minute to produce a curd depth of about l2 inches. The beltspeeds would be adjustable to permit variation of curd throughput.

The illustrated embodiment is advantageous in that it is now possible toadjust the depth of the curd layer during stirring so that drainage isfacilitated, while subsequently operating with a greater depth of curdso that consolidation is facilitated. The stirring arrangement assistsrather than impedes the movement of the curd, and the formation ofchannels along whch whey can run is preferred to simple lifting of thecurd. The action of the stirrer can be made much more gentle than beforeand this reduces fat losses and losses of fines due to particle dmaage.The chains and sprockets can be located completely outside the confinesof the belt so that the chain drive does not approach the curd layer.

The same apparatus can be used for production of stirred curd or hardgrating cheese, and in this case belts l4 and 20 can be operated at thesame speed. Curd agitators of known type can be mounted over belt 20primarily for use in production of this type of cheese. These additionalagitators can be rendered ineffective during production of Cheddar typecheese.

FIG. 3 illustrates an alternative form of stirring finger which can alsobe used in conjunction with crossbar 34. Each of the alternative fingerscomprises a blade-like portion 40 and a screw-threaded shank 42extending away therefrom. Each finger is mounted on the crossbar byco-operation of its shank 42 with a respective screw threaded boss 44mounted in the crossbar. Each finger is locked with its blade at adesired angle relative to the direction of movement of the crossbar bymeans of a respective lock nut 46.

The angle of each blade to its direction of movement is chosenin'accordance with the degree of distrubance it is desired to impart tothe curd the greater the angle, the greater the disturbance. The desireddegree of disturbance in turn depends upon the required final mosturecontent and the characteristics of the curd fed to the machine. Thelatter may vary seasonally. Usually the blades are set at about 45, totheir direction of movement and required adjustments are made from thisnorm. The speed of the chains and crossbars can also be adjusted to varythe disturbance imparted to the curd. The angles of the blades onsuccessive crossbars 34 would be opposed so that curd moved by one setof blades would be returned by the succeeding set. There may be a degreeof variation in the angles of the blades carried by any one crossbar ifthis is found necessary to prevent build up of curd on any particularline along the conveyor.

The invention is not limited to details of the embodiment illustrated inthe drawings. The chain speed may be variable to permit adjustment ofthe amount of stirring obtained, a slower speed giving a more gentlestirring action. The illustrated form of stirrer may be used in otherconveyor arrangements, and may also be used as an additional curdagitator in association with belt during production of Colby cheese. Ifthis stirrer is used with a single conveyor belt, an initial portion ofthe upper run of the belt may be inclined upwardly to assist run-offwhey and the stirrer may be disposed above this portion of the belt. Theremainder of the upper run can then be substantially horizontal. Thedegree of inclination of the belt 14 and the inclined portion of thebelt in this latter variation can be made adjustable. The stirrer itselfis not limited to the particular forms illustrated in the drawings. Anysuitable number of stirring fingers may be provided in each set and anysuitable number of sets may be used. Also, arrangements may be made tooscillate the crossbars, or the fingers carried thereby, as the chainsmove forwardly along the conveyor, but it is believed that this addedcomplication does not significantly improve the effect obtained withoutoscillation.

The present invention may be used in a process, and in conjunction withapparatus, as described in United Kingdom Patent No. 1243957 However, itis not limited to use in that context. Australian Application No.26,955/67 referred to herein corresponds with U.S. Pat. No. 3,523,367(filed 6th Sept., 1968), United Kingdom Patent No. 1243957 correspondswith U.S. Patent Application No. 6915 (filed 29th Jan. 1971).

The second aspect of the invention is not limited to production of alayer of curd which is continuous from the infeed to the outfeed end ofthe system. The curd on the second conveyor may not be formed into alayer at all, but into a succession of heaps spaced along the conveyor.This may be advantageous in permitting improved run-off of whey formedduring the consolidation stage of the process. In this case, the secondconveyor could be operated intermittently and the speed of the conveyormust be considered in terms of the effective speed at which the curd isconveyed over a period, rather than the actual speed at which theconveyor moves when it is operative.

Also, the second conveyor may not be in the form of a continuous belt.If the curd is to be conveyed, at this second stage, as a succession ofseparate bodies, those bodies could be carried in separate containers.Hence the second conveyor could be in the form of a plurality of bucketsconveyable in succession around a closed path and receiving curd fromthe first conveyor.

1 claim:

1. Apparatus for use in processing curd in the manufacture of cheesecomprising: a first conveyor arranged to convey a body of curd, and aplurality of curd sitting devices movable in succession along anelongated path which extends along the conveyor in the direction ofmovement of the body of curd, each of said devices extending toward theconveyor when each of said devices extend into the body of curd to stirit while moving along said path, said path extends forwardly of thefirst conveyor from an infeed end thereof, the speed of movement of eachof said devices along said path is different than the speed of the curdin the same direction; and each of said devices includes a plurality offingers spaced transversely of said path while being moved along it.

2. Apparatus as defined in claim 1 wherein the speed of movement of eachof said devices along said path is greater than the speed of the curd inthe same direction.

3. Apparatus as defined in claim 1 further comprising a second conveyormeans arranged such that curd from a layer of curd formed on the firstconveyor can be transferred to the second conveyor means so as to form abody of curd thereon, the first conveyor and the second conveyor meansbeing operable at different effective speeds so that the depth of thelayer on the first conveyor can be made less than the depth of the bodyon the second conveyor means.

4. Apparatus as claimed in claim 3 wherein the layer of curd formed onthe first conveyor is continuous with a layer formed on the secondconveyor means.

5. Apparatus as claimed in claim 3 wherein each of said devices areprovided to stir the curd on the first conveyor so as to facilitatedrainage of liquid therefrom.

1. Apparatus for use in processing curd in the manufacture of cheesecomprising: a first conveyor arranged to convey a body of curd, and aplurality of curd sitting devices movable in succession along anelongated path which extends along the conveyor in the direction ofmovement of the body of curd, each of said devices extending toward theconveyor when each of said devices extend into the body of curd to stirit while moving along said path, said path extends forwardly of thefirst conveyor from an infeed end thereof, the speed of movement of eacHof said devices along said path is different than the speed of the curdin the same direction; and each of said devices includes a plurality offingers spaced transversely of said path while being moved along it. 2.Apparatus as defined in claim 1 wherein the speed of movement of each ofsaid devices along said path is greater than the speed of the curd inthe same direction.
 3. Apparatus as defined in claim 1 furthercomprising a second conveyor means arranged such that curd from a layerof curd formed on the first conveyor can be transferred to the secondconveyor means so as to form a body of curd thereon, the first conveyorand the second conveyor means being operable at different effectivespeeds so that the depth of the layer on the first conveyor can be madeless than the depth of the body on the second conveyor means. 4.Apparatus as claimed in claim 3 wherein the layer of curd formed on thefirst conveyor is continuous with a layer formed on the second conveyormeans.
 5. Apparatus as claimed in claim 3 wherein each of said devicesare provided to stir the curd on the first conveyor so as to facilitatedrainage of liquid therefrom.